The overall goal is to understand the mechanism and regulation of immunoglobulin gene (Ig) transcription during lymphocyte differentiation and of cellular oncogene (c-myc) transcription during cell growth and lymphoid cell tumorigenesis. The major objective is to determine the nature and mechanism of action of the transcription factors (proteins) which mediate these processes, particularly those which are gene-\or tissue-specific. In the case of Ig genes a search will be made for factors which interact with the Ig-specific enhancer sequences and for additional factors which may be responsible for the elevated levels of transcription in plasma cells. The general approach is to use cell-free systems to identify and study these factors. Using murine plasma-cytoma-derived extracts the aims are to: (1) identify and purify "common" factors (used generally by other pol II genes) using purified DNA templates, as well as cell-gene-specific regulatory factors which act directly at the DNA level; (2) using minichromosomes assembled in vitro, or in vivo with appropriate vectors, search for regulatory factors whose effects are mediated through chromatin structural perturbations; (3) analyze the molecular mechanisms (e.g., site-specific DNA and minichromosome interactions) by which these factors operate; and (4) study the cell/developmental specificity and function of these factors. In the case of the cellular myc gene the objectives are to study the cell cycle regulation in nontumorigenic cells, including a possible autoregulatory mechanism, and the deregulation of myc in lymphoid tumors, including the utilization of normal Ig gene controls. The methods to be used to investigate these aspects of myc transcription, and the protein factors involved, are the same as those described above for Ig genes. (AB)